Production of carbon tetrachloride from carbon bisulfide



March 12, 1963 E. sALLER -ETAL 3,081,359

PRODUCTION OF CARBON TETRACRLORIOE FROM CARBON BISULFIOE Filed July 29.1959 52 Clz B MMA/RM' United States Patent O ntiilw PRGDUCTION @ilCARBON TETRACHLQRDE FROM CAREN BISULFDE Erik Sailer, Tonawanda, NX.,Robert Timmerman, Charleston, W. Va., and Carroll if. Wenzhe, Peekskill,NX., assignors to FMC Corporation, a corporation ci Delaware Filed .luly29, i959, Ser. No. 830,60 9 Claims. (Ci. idd-664) This invention relates-to theproduction of carbon tetrachloride from carbon bisuliide.

' In this specification all percentages and parts are on a Weight basis.

In the chlorination of carbon -bisulde the following exothermic reactiontakes place:

This reaction goes to completion; however, for the economical productionof carbon tertchloride t-he sulfur monochloride must be utilized. Thesulfur monochloride can be` reacted with fresh carbon bisuliide inaccordance with the following equation:

This reaction is exothermic and proceeds to an equilibrium of about 75%completion.

Many procedures have been suggested to combine these reactions andminimize the difficulty of sepa-arting the carbon tetrachloride from thesulfur monochloride and sulfur formed. All such procedures heretoforeproposed have been found objectionable for a number of reasons, amongthe more important of which may be mentioned: (1) they involve therecycle of relatively large amounts of sulfur monochloride; (2) theyinvolve the recycle of elemental sulfur through the chlorination stage;and (3) they involve utilizationy of reaction conditions requiringrelatively long periods of time to go to substantial completion, withconsequent long hold-up times.

lt is among the objects or the present invention to provide a processoi: producing carbon tetrachloride from carbon bisuliide which involvesrelatively shorthold-u-p times, does not involve the recycle ofelemental sulfur through the `chlorination stage, and involves therecycle of relatively small amounts of sulfur monochloride.

Another object of this invention is to provide such process which iscontinuous, or continuous for all practical purposes.

Other objects and advantages of this invention will be apparent from thefollowing detailed description thereof.

In accordance with this invention, carbon tetrachloride is produced byreacting a mixture of carbon bienlfide, carbon tetrachloride and sulfurmonoohloride, produced in a subsequent step of the process, withchlorine to form a reaction mixture containing as its essentialconstituents carbon tetrachloride and sulfur monochloride; this reactionmixture is distilled to separate the carbon tetrachloride overhead fromthe sulfur monochlochloride; the sulfur monochloride, thus separatedfrom the carbon tetrachloride, is reacted with carbon bisulr'ide toproduce a reaction mixture containing carbon bisulide, carbontetrachloride, sulfur monochloride and sulfur; the reaction mixture thusproduced is heated to a temperature below the boiling point of sulfurbut above the boiling point of sulfur monochloride, to drive offoverhead carbon bisultide, sulfur monochloride and carbon tetrachloride,and thus effect a separation of these constituents from the elementalsulfur; and the mixture ofcarbon bisultide, sulfur monochloride andcarbon tetrachloride thus sepa-rated from the sulfur is introduced intothe iirst step abo-ve mentioned. The sulfur thus separated, if desired,may be employedin accordance with any conventional ICC procedure toproduce additional carbon bisuliide which is utilized in the processhereinabove described.

The process is carried out continuously. The chlorination, which may beeffected in a single sta-ge oriin.

multiple stages at a temperature of from 50=105 C., is conducted toproduce at the exit end of the chlorination zone a mixture of carbontetrachloride and sulfur monochloride containing some but not exceeding0.1% carbon bisulde. By observing this precaution of leaving a smallamount of carbon bisulde in the reaction mixture and operating under therecited temperature conditions, and -with no excess of chlorine, thepresence of sulfur dichloride in the reaction mixture introduced intothe still Where separation of the carbon tetrachloride and sulfurmonochloride is effected, is minimized. The amount of chlorine used isthe stoichiometric amount or slightly more (sa-y, about 1% or less) thanthat required to react with all of the carbo-n bisuliide present toproduce carbon tetrachloride. The mixture fed to the chlorinator,containing from to 35%, preferably 10% to 25% of carbon bisuliide, from25% to 45%, preferably 35% to 45% carbon tetrachloride, and froml 25% to45%, preferably 35% to 45% sulfur monochloride is stored under a blanketof inert gas such as nitrogenV because it is tiammable.

From the chlorinator, the reaction mixture, containing as its twoprincipal components, carbon tetrachloride and sulfur monochloride, isseparated continuously by fractional distilla-tion in a column stillpreferably operating under atmospheric pressure conditions. Thisdistillation is carried out to minimize the amount of sulfurmono-chloride which goes overhead with the carbon tetrachloride and sothat a controlled amount, preferably from 3% to 7%, or" carbontetrachloride is present in the bottoms. Such amount of carbontetrachloride in the bottoms tends to retard decomposition of sulfurmonochlo-ride into chlorine and sulfur during the distillation. Byemploying a column having the necessary number of theoretical plates andwith return of a portion of the condensate as reflux, such separationcan readily be effected.

The bottoms, consisting of sulfur monochloride containing a small amountof carbon tetrachloride as above disclosed, may be refrigerated to about-6 C. and used to scrub the vent gas from the chlorination. The result*ant mixture is introduced into a reactor (hereinafter sometimes referredto as a mixer) where it reacts with carbon bisuliide. The carbonbisuliide introduced into the mixer desirably is produced by vaporizingthe incoming carbon bisulfideV and superheating the vapors to about 290to 240 C. The superheated vapors are passed through the elemental sulfurproduced in a subsequent stage of the process to remove from the sulfur,sulfur monochlo-ride, carbon tetrachloride and carbon bisulde. Theresultant vapor stream is then introduced into the mixer for admixturewith the sulfurmonochloride.

Preferably there is admixed with the bottoms from the stiil, before itenters into the mixer, a small amount oi chlorine. Desirably, the amountof chlorine thus mixed with the bottoms is enough to react with thesulfur rnonochloride present to form from 1% to 5% sulfur dichloride inthe bottoms stream entering the mixer. r[his small amount of sulfurdichloride appears to catalyze the Reaction 2 above.

rfhe proportions of carbon bisuliide and sulfur monochloride thuscontinuously supplied to the mixer are controlled to feed about 0.5 molof carbon bisulde per mol oi sulfur monochloride to the mixer, desirablyfrom 0.5 to 1 mol of carbon bisuliide per mol of sulfur monochloride. Byso doing and by observing the other conditions herein disclosed, theamount of sulfur monochloride left in the reaction mixture is kept at. aminimum with consequent recycle of relatively small amounts of sulfurmonochloride.

The mixer operates under reux conditions. Preferably a further catalystis supplied, such as iron, which may be from the walls of the vessel inwhich the reaction is carried out. The preferred further catalyst isferrie chloride added in amount of from 15 ppm. to

2-3% by weight of the charge introduced into the mixer. Under theseconditions and with the ratio of sulfur monochloride to carbon bisultidehereinabove disclosed, the reaction requires only a few hours to reachequilibrium. Hence, the process can be carried out continuously withshort hold-up times.

From the mixer the reaction mixture thus produced is heated to atemperature of about 200 C. and pumped to a flash tank. 4In this heaterand ash tank a certain amount of the carbon tetrachloride present reactswith sulfur to form carbon bisuliide and sulfur monochloride, i.e. somereversion of carbon tetrachloride takes place, which reversion isunavoidable.

The vapors thus ashed ott, and consisting of a mixture containing fromabout 10% to 20% carbon bisultide, from 30% to 45% carbon tetrachlorideand from 35% to 55% sulfur monochloride, pass into a condenser; thecondensate flows to the chlorination treatment. The molten sulfur,containing from 5% to 20% sulfur monochloride and still smaller amountsof carbon tetrachloride and carbon bisulfidepasses from the flash tankinto a stripper where, as above described, it is contacted with carbonbisultide vapors, thus recovering sulfurmonochloride and carbonbisullide in the sulfur. The residual sulfur is purified, for example,by steam stripping or, alternatively, by washing the molten sulfur at atemperature within the range of 120 to 160 C. with a dilute causticsolution or water under a pressure of about 3 atmospheres, permittingthe reaction mixture to stratify into two layers, one, an upper aqueouslayer containing dissolved chlorides and sultes, and the other, thelower pure molten sulfur layer, and withdrawing the thus puri- -iedsulfur; the latter can be converted, if desired, to carbon bisultide byconventional techniques, or otherwise utilized.

The accompanying drawing is a ow sheet showing one preferred arrangementof equipment for practicing the process of this invention.

In this drawing, indicates the chlorination stage or step involving achlorinator 11 which communicates with tank 12 for receiving the mixtureof carbon bisulde, carbon tetrachloride and sulfur monochloride. In theembodiment of the invention shown in the drawing a single stagechlorinator is disclosed in which chlorine is introduced into thechlorinator 11 through line 15, and vapors generated are condensed incondenser 14 and the condensate fed to the chlorinator 11. Thechlorination reaction mixture is recycled through chlorinator 11,llowing through line 9, feed tank 12, pump 16 and back to thechlorinator through line 17. Feed tank 12 is continuously supplied withthe mixture of carbon bisulide, carbon tetrachloride and sulfurmonochloride through line 13 leading from the flash still condenser 44,hereinafter described. Preferably a portion of the carbon bisulide isintroduced into tank 12 directly from storage tank 45 through line il.

Instead of a single stage chlorination, multiple stage chlorination maybe employed, as disclosed in application Serial No. 833,573 tiled August13, 1959.

Chlorination is carried out so as to produce a chlorinated reactionmixture containing as the principal components, carbon tetrachloride andsulfur monochloride, and from 0.03% to 0.10% carbon bisulde. In theembodiment shown in the drawing, a portion of the recycle stream iswithdrawn continuously through discharge line l13; this stream containscarbon tetrachloride, sulfur monochloride and a small amount of carbonbisultide.

` This reaction mixture is pumped continuously by pump 21 into a columnstill 22 provided with a reboiler 23. Carbon tetrachloride is taken offoverhead through line 24, condensed in condenser 25, a portion of thecondensate is returned as reux liquid through line 26, and the remainderremoved through line 27 as crude carbon tetrachloride product. Thiscrude carbon tetrachloride may be purified in any known manner or by theprocedure disclosed in co-pending application Serial No. 820,- 363 tiledJune 15, 1959, now Patent No. 2,945,796.

Chlorine may be supplied through line 29 for adrnixture with the bottomsto react with sulfur monochloride therein to form a small amount ofsulfur dic'nloride, which as above noted catalyzes the reaction betweencarbon bisullide and sulfur monochloride to form carbon tetrachlorideand sulfur.

The bottoms from column 22, if desired, may be refrigerated to atemperature of about -6 C. in a refrigerator 31 communicating with anabsorber 32 through which passes the vent gas (non-condensiole gasesproduced in the chlorinator) from the chlorinator 11. This vent gas isintroduced into the absorber 32 through line 33 at the base of theabsorber. It then passes from the absorber 32 to a scrubber 34 where thegas is scrubbed with water to remove noxious fumes which may be present.By so doing, losses of valuable constituents in the vent gases areminimized.

Sulfur monochloride from the absorber 32, containing carbon bisulde, asmall amount of sulfur dichloride formed yby reaction of the smallamount of added chlorine with the sulfur monochloride, and a smallamount of carbon tetrachloride removed from the vent gas, passes to thefirst of a pair of mixers 35, 36. These mixers operate under reiluxconditions and for this purpose communicate with a condenser 37 whichcondenses evolved vapors from both mixers. The condensate flows throughline 38 to mixer 35.

Carbon bisulde vapor from the sulfur stripper 40 is introducedcontinuously into the mixer 35 through line 39. Liquid flows from themixer 35 to mixer 36. Mixers 35 and 36 are dimensioned and the flowrates to and discharge from these mixers are such as to provide ahold-up time in these mixers of about 1 to' 8 hours.

From mixer 35 the reaction mixture is pumped continuously by pump 41through a heater 42 into a liash tank 43. In heater 42 the mixture isheated to from about 180 to about 275 C. preferably from about 200 to240 C. This heating operation vaporizes, of the total fed, about 97% ofthe carbon bisultide, about 96% of the carbon tetrachloride and about ofthe sulfur monochloride. The vapors leave the flash tank 43, passthrough the condenser 44, and the resultant condensate 1s passedcontinuously to the chlorinator feed tank 12 through line 13.

Liquid elemental sulfur, containing a small amount of sulfur chloride(about 7%) and still smaller amounts of carbon tetrachloride and carbonbisulde, passes from llash tank 43 to the sulfur stripper 40. Carbonbisuliide from storage tank 45 passes through a vaporizer d6; theresultant vapors flow through line 47 into and through the sulfur instripper 40, removing from the elemental sulfur, sulfur monochloride,carbon tetrachloride and carbon bisulde. As above described, theresultant stream liows into the mixer 35 through line 39. The elementalsulfur from stripper 40 may be purified 1n any desired manner. Forexample, it may be passed through cooler 48 and thence to steam stripped48 communicating with condenser 51. The purified sulfur 1s. pumped fromthe stripper 49 by pump 52 to the carbon bisulde plant or other suitableplace of utilization. Alternatively, the sulfur may be purified bytreatment with alkali or water as disclosed above.

The following examples are given for illustrative purposes only; it willbe appreciated that this invention is not limited to these exampleswhich illustrate preferred modes of practicing the invention. In theexamples all All poundage values are pounds per hour; temperatures indegrees C.

The examples are carried out in equipment of the general type showninthe drawing, under atmospheric pressure conditions.

Example] In thi-s example all ofthe carbon bisulde feed is introducedinto the stripper 40.

Chlorination is eected by continuously introducing into the chlorinator7,336 pounds of chlorine and 9,180 pounds of a mixture containing 28.6%carbon bisuldc, 26.3% carbon tetrachloride fand `45.1% Sulfurmonochloride, which mixture flows from the liash fstill condenser 4-4.The chlorine 'and carbon vbisulde enter at atmospheric temperature(about 25 C.) and the said mixture at a temperature of `40 C. VThetemperature at the exit end of the chlorinator is 105 C.

16,516 pounds of chlorinated material is pumped from the chlorinatorinto still `22 operated at a bottoms temperature of about 135 C. and ata temperature of '78 C. at its top. This material introduced intostill22. contains 0.05% carbon bisull'ide, 46.65% ycarbon tetrachloride, 53%sulfur'monochloride and 0.3% sulfur dicliloride. The overhead streamfrom still 22 in amount of 8,476 pounds contains 0.1% carbon bisulde,98.9%

carbon tetrachloride, 0.4% sulfur monochloride and 0.6% sulfurdichloride. The bottoms stream from this still in Vamount of A8,040'pounds contains 4.5% carbon tetrachloride and 95.5% sulfur monochloriderIltis stream is mixed with 116 pounds of chlorine. A reaction Vtakesplace between the chlorine and the sulfur mono chloride. There is thusproduced a stream in amount of 8,156 pounds containing 4.4% carbontetrachloride, 91.5% sulfur monochloride and 4.1% sulfur dichloridewhich is introduced into the mixer 35 at a temperature of about 100 C.Also introduced into the mixer is a stream from the sulfur stripper 40in amount of 3,848 pounds consisting of 95.8% carbon bisullide and 4.2%sulfur monochloride; the temperature ofthe latter stream is 220 C. Themixer 35 .is maintained underreiiux conditions.

There is removed from the mixer a stream in amount of 12,000 poundsconsisting of 22.1% carbon bisulde, 20.4% carbon tetrachloride, 36.6%sulfur monochloride and 20.9% sulfur. This stream is heated to 200 C.and the heated material is introduced into the ash tank 43. There istaken overhead from this Hash tank a stream in amount of'9,180 poundsconsisting of 28.6% carbon bisuliide, 26.3% carbon tetrachloride and45.1% sulfur moncchloride which is condensed and the condensateintroduced into the chlorinator as hereinabove described.

There is removed as bottoms from the ash tank 43 a stream in amount of`2,820 pounds consisting of 0.8% carbon bisulfide, 1.4% carbontetrachloride, 8.8% sulfur monochloride and 89% sulfur. This stream isintroduced into the sulfur stripper 40 where it is stripped with 3,668pounds of carbon bisullide vapor producing the overhead stream in amountof 3,848 pounds containing 95.8% carbon bisultide and 4.2% sulfurmonochloride introduced into the mixer-'35. There is removed as bottomsfrom the sulfur stripper 2,636 pounds consisting oi 0.2% carbonbisuliide, 1.5% carbon tetrachloride, 3.2% sulfur monochloride and 95.1%sulfur.

:Exmnple Il pounds otra mixture containing '29.4% carbon bisultide,

36.6% carbon tetrachloride, 33.5% 'sulfur monochloride land 0.5% sulfurdichlor-ide, which mixture ilovvs from the flash still condenser 44 andcontains, in addition to 4the mixture from the condenser 44, 2,329pounds of canbon bisu'liide rfeed. The chlorine and carbon bisnlfideSenter lat atmospheric temperature (about 25 C.) and the said mixture ata temperature of 40 C. The temperature at the exit end of thechlorinator is C.

20,829 pounds of ohlorinatedmate'rial is pumped tfrom lthe chlorinatorinto still 22 operated at a bottoms ten amount of 10,749rpoundscontaining 7.9% carbon tetrachloride, 88.1% sulfur monochloride and 4%sulfur dichloride which is introduced into the mixer 3S at a temperatureof about 100 C. Also introduced into this mixer is a stream lfrom thesulfur stripper 40 in amount of 3,154 .pounds consisting of 87.2%carbon' bisuliide, 1.5% carbon tetrachloride and 11.3% sulfurmonochloride; the temperature of the latter stream is 220 C. The mixer35 is maintained under reflux conditions.

There is removed from the mixer a stream in amount of 13,903 poundsconsisting of 7.6% carbon bisuliide, 31.1% canbon tetrachloride, 30.86%sulfur monos-hicride, 0.44% sulfur dichloride `and 30% sulfur. Thisstream is heated to C. and the heated materia-l yis introduced into theflash tank 43. There is taken overhead from this flash tank a stream inamount of 9,121 pounds consisting of 11.4% carbon bisulde, 45.9% carbontetrachloride, 42.1% sulfur monochloride and 0.6% sulfur dichloridewhich .is condensed and the condensate introduced into the chlorinatoras hereinabove described.

There is removed as bottoms from the flashtank 43 a stream in amount of4,782 pounds consisting of 0.3% carbon bisulde, 2.9% carbontetrachloride, 9.6% sulfur monochloride and `87.2% sulfur. This streamis introduced into Ithe sulfur stripper 40 Where it is stripped with2,737 pounds of carbon bisultidev vapor producing the overhead stream inamount of 3,154 pounds consisting of 87.2% carbon bisulde, 1.5% carbon'tetrachloride and 11.3% sulfur monochloride introduced into the mixer35. There is lremoved as bottoms from the sulfur stripper 4,365 poundsconsisting of 0.135% carbon bisuliide, 2.04% carbon tetrachloride, 2.34%sulfur monochloride and 95.485% sulfur.

carbon bisulde feed is supplied to the stripper 40 and the remainder -tothe chlorinator.

Chlorination is effected by continuously introducing,y into thechlorinator 10,190 pounds of chlorine and 11,622 pounds of amixturecontaining 30.8% carbon bisuliide, 36.4% carbon'tetrachloride, 30.6%sulfurmonochloride and 2.2% sulfur dichloride, which mixture lloWs fromthe flash still condenser 44 and contains, in addition to lthe mixturelfrom the condenser 44, 2,449 pounds of carbon bisultide-feed. Thechlorine and carf bon bisuliide enter at atmospheric temperature (about25 C.) and the said mixture at a temperature of 40 C. The temperature atthe exit end of the chlorinator -is 100 C.

21,812 pounds of chlorinated material is pumped from thechlorinatorintostill 22 operated at .a bottoms tern- `perature of about 136 C. andat a temperature of 78 C.

atits top. Thechlorinated material introduced intostill The bottomsstream from 22 contains 0.04% carbon bisultide, 54.16% carbontetrachloride, 45.5% sulfur monochloride and 0.3% sulfur dichloride. Theoverhead stream from still 22 in amount of 11,188 pounds contains 0.08%carbon bisultide, 98.92% carbon tetrachloride, 0.4% sulfur monochlorideand 0.6% sulfur dichloride, The bottoms stream from this still in amountof 10,624 pounds contains 6.9% carbon tetrachloride and 93.1% sulfurmonochloride. 165 pounds of chlorine is added to this stream. Thechlorine reacts with the sulfur monochloride producing a mixture inamount of 10,789 pounds containing 6.8% carbon tetrachloride, 88.4%sulfur monochloride and 4.8% sulfur dichloride which is introduced intothe mixer 35 at a temperature of about 100 C. Also introduced into thismixer is a stream .from the sulfur stripper 40 in amount of 3,408 poundsconsisting of 85.3% carbon bisultide, 2.6% carbon tetrachloride, 10.6%sulfur monochloride and 1.5% sulfur; the temperature of the latterstream is 220 C. The mixer 35 is maintained under reflux conditions.

There is removed from the mixer a stream in amount of 14,197 poundsconsisting of 5.9% carbon bisultide, 35.2% carbon tetrachloride, 20.5%sulfur monochloride, 1.8% sulfur dichloride and 36.6% sulfur. Thisstream is heated to 200 C. and the heated material is introduced intothe flash tank 43. There is taken overhead from this ash tank a streamin amount of 9,173 pounds consisting of 12.3% carbon bisullide, 46.2%carbon tetrachloride, 38.7% sulfur monochloride and 2.8% sulfurdichloride which is condensed and the condensate introduced into thechlorinator as hereinabove described.

There is -removed as bottoms `from the liash .tank 43 a stream in amountof 5,024 pounds consisting of 0.4% carbon bisulde, 2.8% carbontetrachloride, 9.0% sulfur monochloride and 87.8% sulfur. This stream isintroduced into the sulfur stripper 40 where it is stripped with 100pounds of carbon bisulde vapor producing the overhead stream in amountof 3,408 pounds consisting of 85.3% carbon bisultide, 2.6% carbontetrachloride, 10.6% sulfur monochloride and 1.5% sulfur introduced intothe mixer 35. There is removed as bottoms `from the sul-fur stripper4,505 lpounds consisting of 0.1% carbon bisullide, 1.1% carbontetrachloride, 2% sulfur monochloride and 96.8% sulfur.

It will be noted that the present invention provides a continuousprocess of producing carbon tetrachloride from carbon bisultideinvolving relatively short hold-up times, the recycle of relativelysmall amounts of sulfur monochloride, and the substantially completeutilization of the carbon bisulde introduced into the process and sulfurmonochloride formed in the process, in the production of carbontetrachloride. Moreover, the present invention does not involve therecycle of elemental sulfur through the chlorination stages but itsremoval from the process as formed; the sulfur thus removed can beconverted to carbon bisultide for use in the process.

Since different embodiments of the invention could be made withoutdeparting from the scope of this invention, it is intended that allmattei' contained in the above description or shown in the accompanyingdrawing shall be interpreted as illustrative and not in a limitingsense.

What is claimed is:

1. The continuous process of producing carbon tetrachloride from carbonbisulde which comprises the following steps: step l, continuouslyflowing a mixture of carbon bisultide, carbon tetrachloride, sulfurmonochloride and chlorine through a chlorination zone at a ternperatureof from 50 C. to 105 C., and removing from the exit end of saidchlorination zone a reaction mixture of carbon tetrachloride and sulfurmonochloride containing from 0.03% to 0.10% carbon bisulde; step 2,continuously distilling the reaction mixture thus withdrawn from step 1to take oli` overhead the carbon tetrachloride Vand remove as bottomsthe sulfur monochloride; step 3, continuously mixing the sulfurmonochloride thus removed from step 2 with a stream of carbon bisultideand reacting the resultant mixture to produce a reaction mixturecontaining carbon bisulde, carbon tetrachloride, sulfur monochloride andsulfur; step 4, continuously heating the reaction mixture from step 3 toa temperature above the boiling point of sulfur monochloride, but belowthe boiling point of sulfur and introducing the heated reaction mixtureinto a liashing zone to ash oi and thus separate a vapor mixtureconsisting essentially of carbon bisultide, carbon tetrachloride andsulfur monochloride from the sulfur; step 5, continuously introducingsaid mixture from step 4 into step 1 of the process and continuouslywithdrawing the sulfur produced in step 4 from step 4.

2. The continuous process as defined in claim l, in which the carbonbisuliide and sulfur monochloride are mixed in a mol ratio of from about0.5 to about 1 carbon bisultide per mol of sulfur monochloride.

3. The continuous process as delined in claim l, in which the sulfurremoved from step 4 is stripped with carbon bisulde vapor to remove fromthe sulfur, sulfur monochloride and carbon tetrachloride, and theresultant carbon bisulfde vapor stream containing the extracted sulfurmonochloride and carbon tetrachloride is introduced into step 3 forreaction With the sulfur monochloride.

4. The continuous process as defined in claim 1, in which the vent gasesfrom step 1 are scrubbed with the sulfur monochloride removed from step2 and the resulting sulfur monochloride mixture is reacted with thecarbon bisulde in step 3.

5. The continuous process as defined in claim 1, in which the sulfurmonochloride removed from step 2 is reacted with the carbon bisuliide inthe presence of an iron catalyst to produce the reaction mixturecontaining carbon bisultide, carbon tetrachloride, sulfur monochlorideand sulfur.

6. The continuous process as defined in claim 1, in which the reactionmixture from step 3 is heated to a temperature within the range of aboutto 275 C. and the thus heated reaction mixture is introduced into aflash tank to distill off the mixture of carbon bisultide, carbontetrachloride and sulfur monochloride.

7. The continuous process as defined in claim 1, in which a small amountof chlorine is added to the sulfur monochloride removed from step 2 toreact with the sulfur monochloride and form sulfur dichloride, and theresultant mixture is reacted with carbon bisulide to produce thereaction mixture containing carbon bisulfide, carbon tetrachloride,sulfur monochloride and sulfur.

8. The continuous process as defined in claim 7, in which the amount ofchlorine added to the sulfur monochloride removed from step 2 is such asto produce from 1% to 5% by weight of sulfur dichloride in the mixtureadmixed with the carbon bisulide for reaction therewith.

9. The continuous process of producing carbon tetrachloride from carbonbisullide which comprises the following steps: step 1, continuouslyflowing a mixture containing from 10% to 35% carbon bisulide, from 25%to 45% carbon tetrachloride, from 25% to 45% sulfur monochloride andabout the stoichiometric amount of chlorine required to react with thecarbon bisultide to produce carbon tetrachloride through a chlorinationzone at a temperature of from 50 to 105 C., and removing from the exitend of said chlorination zone a reaction mixture of carbon tetrachlorideand sulfur monochloride containing small amounts of carbon bisultide;step 2, continuously distilling the reaction mixture thus removed fromstep l to take ot overhead the carbon tetrachloride and remove asbottoms the sulfur monochloride; step 3, continuously mixing the sulfurmonochloride thus removed from step 2 with a stream of carbon bisultidein amounts ranging from 0.5 to 1 mol of carbon bisulde per mol of sulfurmonochloride and reacting said mixture to produce a reaction mixturecontaining carbon bisulide, carbon tetrachloride, sulfur monochlorideand sulfur; step 4, continuously heating the reaction mixture from step3 to from 180 to 275 C. and introducing the heated reaction mixture intoa ashing Zone to flash off and thus separate a vapor mixture consistingessentially of from 10% to 20% carbon bisulde, from 30% to 45% carbontetrachloride and from 35% to 55% sulfur monochioride from the sulfurresidueystep 5, continuously condensing said vapor mixture from step 4,mixing same with chlorine and carbon bisulde and introducing theresultant admxture into step 1 of the process.

References Citerl in the file of this patent UNITED STATES PATENTSDoeringer May 16, 1911 Baillio Mar. 26, 1918 Erallier et al Aug. 4, 1931Nichols Oct. 8, 1935 Reilly Mar. 8, 1938 Belanblossom et al. Apr. 13,1943 Beanblossorn et al Apr. 13, 1943

1. THE CONTINUOUS PROCESS OF PRODUCING CARBON TETRACHLORIDE FROM CARBONBISULFIDE WHICH COMPRISES THE FOLLOWING STEPS: STEP 1, CONTINUOUSLYFLOWING A MIXTURE OF CARBON BISULFIDE, CARBON ETRACHLORIDE, SULFURMONOCHLORIDE AND CHLORINE THROUGH A CHLORINATION ZONE AT A TEMPERATUREOF FROM 50* C. TO 105* C., AND REMOVING FROM THE EXIT END OF SAIDCHLORINATION ZONE A REACTION MIXTURE OF CARBON TETRACHLORIDE AND SULFURMONOCHLORIDE CONTAINING FROM 0.03% CARBON TETRACHLORIDE AND REMOVE ASTILLING THE REACTION MIXTURE THUS WITHDRAWN FROM STEP 1 TO TAKE OFFOVERHEAD THE CARBON TETRACHLORIDE AND REMOVE AS BOTTOMS THE SULFURMONOCHLORIDE; STEP 3, CONTINUOUSLY MIXING THE SULFUR MONOCHLORIDE THUSREMOVED FROM STEP 2 WITH A STREAM OF CARBON BISULFIDE AND REACTING THERESULTANT MIXTURE TO PRODUCE A REACTION MIXTURE CONTANING CARBONDISULFIDE, CARBON TETRACHLORIDE, SULFUR MONOCHLORIDE AND SULFUR; STEP 4,CONTINUOUSLY HEATING THE REACTION MIXTURE FROM STEP 3 TO A TEMPERATUREABOVE THE BOILING POINT OF SULFUR MONOCHLORIDE, BUT BELOW THE BOILINGPOINT OF SULFUR AND INTRODUCING THE HEATED REACTION MIXTURE INTO AFLASHING ZONE TO FLASH OFF AND THUS SEPARATE A VAPOR MIXTURE CONSISTINGESSENTIALLY OF CARBON BISULFIDE, CARBON TETRACHLORIDE AND SULFURMONOCHLORIDE FROM THE SULFUR; STEP 5, CONTINUOUSLY INTRODUCING SAIDMIXTURE FROM STEP 4 INTO STEP 1 OF PROCESS AND CONTINUOUSLY WITHDRAWINGTHE SULFUR PRODUCED IN STEP 4 FROM STEP 4.